340 SUMMARY OF CURRENT RESEARCHES RELATING TO 



described by Chmielevsky for Spirogyra, and considers that Basidiooolus 

 must be related to that alga. 



Conidial Stage of Morchella.* — Gaston Bonnier gives the results 

 of his experimental cultures of various species of Morchella. The asco- 

 spores were easily made to germinate, and formed a sterile mycelium 

 very similar in the different species tested. No conidial formation could 

 be induced in the artificial cultures, but when the spores were sown on 

 suitable soil a further growth was induced, and a conidial form closely 

 similar for several species of Morchella was grown, and was found to be 

 identical with a Hyphomycete discovered and described by Matruchot 

 as Costantinella cristata. 



Development of the Perithecium.f — P. A. Dangeard contributes 

 some observations made on Saccobolus violaceus, Ascophanus ochraceus, 

 and Aspergillus glaucus. In all of these he finds both an ascogonium 

 and pollinodium, but there is no fusion between the two. He finds 

 also that the development of Ascophanus more nearly resembles that of 

 Pyronema than of Saccobolus, and he thinks that such facts might be 

 useful in tracing the affinities of these fungi, and in following the 

 development of the aerial Ascomycetes from the aquatic Siphomycetes. 



Notes on Ceratostoma juniperinum.l — P. Baccarini has examined 

 the tubercles that occur on the branches of the juniper, and on which 

 Ceratostoma has been constantly found growing. The perithecia are 

 always on dead tissue, but the mycelium of the fungus penetrates to 

 the living cells and causes the distortion of the branch. He did not 

 find bacteria in the tubercles, as did Cavara. He considers the injury 

 to be due to Ceratostoma alone. 



Specialisation of Parasitism in the ErysiphaceaeJ — E. S. Salmon 

 publishes a preliminary paper on this subject. He had already pub- 

 lished his experiments proving the existence of " biologic " forms in the 

 Erysiphacea?. He has now carried his research further and finds that 

 there are bridging host species that enable the parasite to pass from one 

 to another. For instance, the mildew on Bromus racemosus is incapable 

 of infecting B. commutatus, but it never fails to infect B. hordeaceus, 

 and the fungus after growing on B. hordeaceus infects B. commutatus. 

 There is no morphological difference to be detected in the fungus on 

 these various grasses. He finds further that there are biologic species 

 or races in the host-plant also without any morphological distinction. 

 The spores of Oiclium from several species of Bromus infected B. hor- 

 deaceus, a Russian form of B. mollis ; the two grasses being morpho- 

 logically identical, while they would not infect the native B. mollis, 

 proving some physiological distinction between the forms. 



The same || writer records still another discovery made by him 

 during his investigation of this subject ; that " under certain methods 

 of culture in which the vitality of the host-leaf is interfered with, the 

 restricted powers of infection, characteristic of ' biologic forms,' break 



* Comptes Eendus, cxxxviii. (1904) pp. 416-17. f Tom. cit., pp. 642-3. 



t Nuovo Giorn. Bot. Ital. xi. (1904) pp. 49-52. 

 § New Pliytolog., iii. (1904) pp. 55-60 (3 ficrs.). 

 1 Proc. Roy. Soc, lxxiii. (1904) pp. 116-18. 



